1. Field
Embodiments of the present invention relate to a fuel supply apparatus, and more particularly, to a fuel supply apparatus for a combustor.
2. Description of the Related Art
A fuel cell is a power generation system that directly converts chemical energy into electric energy by electro-chemically reacting hydrogen and oxygen. A fuel cell may typically be classified as a polymer electrolyte membrane fuel cell, a direct methanol fuel cell, a phosphoric acid fuel cell, a molten carbon fuel cell, and a solid oxide fuel cell. These respective fuel cells are basically operated based on a common principle, but are different in the fuels used, catalysts and electrolytes, and/or other aspects.
A fuel cell generates electricity from a membrane-electrode assembly (MEA) that is referred to as a unit cell. The unit cell has a structure in which catalyst layers are disposed on both sides of an electrolyte membrane which is arranged therebetween. The electro-chemical reaction in the anode electrode and the cathode electrode of a typical fuel cell is represented by the following reaction 1.Anode electrode: 2H2→4H++4e−Cathode electrode: O2+4e−+4H+→2H2O   Reaction 1
Hydrogen is supplied in the anode electrode and the hydrogen is dissolved into hydrogen ions and electrons on the catalyst of the anode electrode. The hydrogen ions are moved to the cathode electrode through the electrolyte membrane and the electrons are moved to the cathode electrode, thereby generating electricity. Oxygen included in the air is supplied to the cathode electrode, and the electrons and hydrogen ions moved from the anode electrode and the oxygen are reacted on the catalyst on the cathode electrode, thereby generating water. The reactions are a sort of catalyst reaction and the reactions efficiently occur in at least a predetermined temperature in view of the characteristics of the catalyst reaction.
Hydrogen used in the power generation of the fuel cell may be supplied by reforming fuel in a reformer. A great quantity of heat is required when reforming fuel so that a separate combustor for supplying heat is commonly added in the reformer.
However, the combustor may be supplied with air together with hydrocarbon fuel, and a flashback phenomenon characterized by flames being flowed backward and/or a blow-off phenomenon in which flames are extinguished may be generated if requirements such as supply temperature of fuel and air, supply linear velocity of fuel and air, or equivalence ratio of fuel to air (λ) are not properly controlled. As a result, there is a need for a special control.
In general, techniques of inserting various structures in order to lower the temperature of fuel or air and increase the linear velocity of fuel and air in an effort to suppress the generation of the flashback phenomenon have been well-known.
However, such conventional techniques have problems of increased costs and an increase in volume of the fuel cell due to the insertion of the structures. Therefore, there is a need for a method of suppressing the flashback phenomenon of the combustor, while providing high efficiency combustion, at a lower cost.